We are using phychophysical and psychomotor measures to study auditory processing in psychiatric patients and non-patients. Our aims are to: (1) discover differences in sensory processing between psychiatric patients and non-patients that are traceable to central nervous system functioning; (2) develop objective "culture-free" indicators of psychopathology. The proposed research attempts to extend our prior findings in which affective psychotics were less sensitive in detecting a single click and showed greater reaction time facilitation to click pairs than schizophrencis and non-patients. Several measures of auditory processing will be administered to groups of affective psychotics, schizophrenics, brain damaged patients, and normal controls. Particular attention was given to selecting auditory measures that may serve as indicators of central auditory dysfunction., e.g., signal detectability of noise bursts of variable duration and binaural summation.